Axial-flow pump



May 5, 1925.

- H. F. BENSON AXIAL FLOW PUMP Filed Feb. l0, 1921 in I.. IIHIIl l .E Nim@ INVENTOR Patented May 5, 1925.

UNITED STATES PATENT OFFICE.

HARRY F. BENSON, OF HOIYOKE, MASSACHUSETTS, ASSIGNOR T0 WORTHINGTON PUMPAND MACHINERYOORPORATION, OF NEW YORK, N. Y., A CORPORATION OF VIRGINIA.

AXIAL-FLOW PUMP.

Application led February 10, 1921. Serial No. 443,830.

To all whom t may concern.'

Be it known that I, HARRY F. BENSON, a citizen of the United States,residing at Holyoke, county of Hampden, and State of Massachusetts, haveinvented certain new and useful Improvements in Axial-Flow Pumps, fullydescribed and represented in the following specification and theaccompanying drawings, forming a part of the same.

This invention relates to pumps of the type wherein an' Vaxial fiowimpeller is located in a cylindrical housing 'for the purpose of movinga fluid through such housing.

The present invention has as its object the provision of a pump of thistype that shall operate with a higher efficiency than previous pumps,and secures this result by a construction in which conversion ordiffusion vanes are spaced from the discharge side of the'impeller toform a conversion chamber of such length as to provide spacein which the.swirling or helical motion of the dis charged streams is graduallydissipated and the streams widen out and finally assume a substantiallyaxial direction of movement, the conversion or diffusion vanes being solocated that the streams enter the vanes at the time of thus assumingsubstantially axial direction.

It has been found that the rate of increase in width or breadth of thestreams leaving the impeller blades and the distance required in turningto substantially an axial direction with consequent decrease in velocityis controlled by the relative location of the conversion vanes withrespect to the impeller, and by the relation between the initialvelocity imparted by the impeller and the final velocity at the point ofentering the conversion vanes. Consequently, by deter mining thesevelocities and their corresponding areas and thus calculating theposition of v*these conversion or diffusion vanes, it is ossible toestablish ya conversion chamber 1n which the kinetic energy of the fluidleaving the impeller may be efectivelycon verted to its final pressure.

In the drawings:

Figure 1 is a vertical section through a pump embodying this invention.

Figure 2 is a transverse section on the line 2-2 of Figure 1.

Figure 3 is a developed vertical section on the line 3 3 of Figure 2.

Referring to the drawings:

Y `The invention` as herein disclosed for the purpose of illustratingthe principle involved. comprises a cylindrical casing A which may bemade up of sections 1, 2 and 3. the section 2 being threaded at each endto receive the ends of the other sections and shouldered as at 4 and 5to seat the conversion or diffusion vane ring 6 and the guide vane ring7. the former of which carries a hub 8 connected with the ring by radialconversion or diffusion Yanes 9 of elliptical cross-section, as shown inFigure 2; while the latter also carries a hub 10 connected with the ring7 by guiding vanes 11, the said hub 10 being tapered toward theentrance. and the inner wall of ring 7 being crowned or curved toprovide passages facilitating entrance of the fluid tothe blades of animpeller 12 mounted on a shaft 12'L running in bearings formed by thehubs 8 and 10. This impeller 12 is of the axial flow type having a hub13 from which the radial screw blades 14 project and which, whendeveloped, appear as in Figure 3, and are shown to have thin entranceedges with curved slightly diverging side walls.

The location of the conversion or diffusion vane ring 6 is such, withrespect to the discharge side of the axial flow impeller 12. that aconversion chamber 15 is established therebetween.

When fluid is delivered to therotating impeller 12 by the guide vanes11. the blades 14 of the impeller discharge Streams havinar adirectional velocity which is the result of the combined action of theimpeller speed as represented by W (Fig. 3) and the relative axialvelocity R. This directional velocity is represented by U in Fig. 3 andindicates the velocity condition of a stream of fiuid thrown'out of theimpeller into the conversion chamber 15. Also, in Fig. 3. theoreticalstream lines F issuing from the impeller into the Vconversion chamber 15form between them curving streams of fluid gradually increasing inbreadth as shown by a, b, c, d, e, and f, at which latter indication thestreams have assumed substantially an axial fiow and have decreased froma high to a relatively low velocity and are entering the conversion ordiffusion vanes, which ensure the axially directed f'luid column againstfurther agitation by eddies or swirling.

The entrance edges of the conversion or diffusion vanes may be placedslightly nearer the impeller than above set forth, in which case acurved entrance may be provided but the location even then iS to be.such that the streams of fluid, theoretically illustrated in Fig. 8.enter the vanes at a small angle and at low velocity.

I claim:

1. In a fluid pump, a casing, an axial flow impeller therein, andconversion vanes in the casing and having their entrance positioned atthe point where the streams leaving the impeller initiate movement inonly an axial direction, whereby a conversion chamber is providedbetween the impeller and said vanes.

2. In a fluid pump, a casing, an axial flow impeller .therein deliveringhelically moving streams gradually decreasing in velocity until theyhave only an axial movement, and axially extending radial conversionvanes in said casing receiving said streams at the point where helicalmovement ceases.

3. In a Huid pump. a casing` an axial flow impeller therein deliveringhelically moving streams graduallydecreasing in velocity until they haveonly an axial movement, and axially extending radial conversion vanes insaid casing and of elliptical cross-section, said vanes positioned toreceive the said streams at the point where the helical movement ceases.

4. In a fluid pump, a casing, a screw impeller therein deliveringhelically moving streams gradually decreasing in velocity until theyhave only an axial movement, and axially extending radial conversionvanes in said casing and of elliptical cross-section, said vanespositioned to receive the said streams at theV point where helicalmovement ceases.

5. In a fluid pump, a casing, an axial flow impeller therein, conversionvanes in said casing and having their entrance positioned at the pointwhere the streams leaving the impeller initiate axial movement only,whereby a conversion chamber is provided, and guide vanes on the suctionside of the impeller.

6. In a fluid pump, a casing, an axial flow impeller therein deliveringhelically moving streams of decreasing velocity and increasing streamarea, and conversion vanes on the discharge side of said impeller andspacedtherefrom to control and maintain the rate of decrease in velocityand increase of stream area and provide a c011- version chamber foreflicient conversion from velocity to pressure.

T. In a fluid pump, a casing, a screw impeller delivering helically'moving streams of gradually decreasing velocity and increasing streamarea, and axially extending radial conversion vanes spaced from theimpeller discharge to provide a conversion chamber and controlling therate of decrease in velocity and increase in stream area whereby saidstreams initiate axial movement only at the movement of entering saidvanes.

8. In a fluid pump, acasing, a screw impeller therein deliveringhelically moving streams gradually decreasing in velocity at a raterequired for effective conversion of velocity into pressure and axiallyextending radial conversion vanes in said casing so positioned as toreceive said streams at the point where the streams have only an axialmovement occurring at a Lzpoint dependent on the said decreasing rate ofvelocity.

9. In a fluid pump, a casing, an axial flow impeller therein, deliveringstreams gradually decreasing in velocity at a. rate required forelective 'conversion of velocity into pressure, and conversion vanes insaid casing so positioned as to receive said streams at the point wherethe streams have only an axial movement occurring at a point dependentonthe said decreasing rate of velocity, whereby a conversion chamber isprovided, and guide vanes on the suction side of the impeller.

In testimony whereof, I have hereunto set my hand.

HARRY F. BENSON.

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